Emitters have a wide range of potential applicability in the microelectronics field. An emitter emits electrons in response to an electrical signal. The controlled emissions form a basis to create a range of useful electrical and optical effects. Prior conventional emitters include spindt tip cold cathode devices.
The geometry of cold cathode spindt tip emitters presents a barrier to size reduction. As the size of a spindt tip device is reduced, the spindt tip becomes more susceptible to damage from contaminants in a vacuum ionized from the emissions from the tip. The ionized contaminants are attracted to the spindt tip and collide with it, thereby causing damage. A vacuum space around the spindt tip therefore requires an increasingly high vacuum to avoid the potential damage caused by ionized contaminants. For similar reasons, the tip geometry is also a barrier to incorporation of emitters with integrated circuits.
Flat emitters are comparably advantageous because they present a larger emission surface that can be operated in lower vacuum environments. Flat emitters include a dielectric emission layer that responds to an electrical field created by other portions of the device. Flat emitters are tunneling emission devices. An electric field proximate the surface of the emission layer narrows a width of a potential barrier existing at the surface of the emission layer. This allows a quantum tunnelling effect to occur, whereby electrons cross through the potential barrier and are emitted from the material.
Flat emission layers formed by low temperature chemical vapor deposition or room temperature sputter/evaporation techniques are potentially unstable. Specifically, such layers often have electrical characteristics that change with time. In addition, layers formed by such processes must be conditioned, e.g., through electro-forming processes. Even with conditioning, significant variation in device performance is possible. Electro-forming is also a time consuming process.